UH researcher links
low calories to longevity
The study of men of Japanese
descent was begun in 1965
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A reduced caloric diet might lead to a longer life, according to a study of Honolulu Heart Program data on 8,006 men of Japanese ancestry.
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Willcox and other researchers from the Pacific Health Research Institute and Kuakini Medical Center wrote an article called "How Much Should We Eat: The Association Between Energy Intake and Mortality in a 36-year Follow-up Study of Japanese-American Men" that is featured in today's Journal of Gerontology Biological Sciences.
The report is believed to be the first long-term study that links reduced caloric intake with the longevity of humans.
"I'm not aware of another study that has such detailed diet information in 40 years of follow-up," said Willcox yesterday in a phone interview from Calgary, Canada.
Interest in the article already had circulated to parts of the mainland.
In 1965 the Honolulu Heart Program at Kuakini Medical Center started to collect data on men of Japanese descent who lived on Oahu. All of the men who ranged between 45 and 68 years old were healthy and nonsmokers.
According to Willcox, the study showed that risk of death dropped a third for men who ate fewer calories of about 1,900 calories a day or about 15 percent fewer than the group average of 2,300 calories a day.
"This trend for lower mortality persisted all the way until people ate 50 percent fewer calories than the group average, which is exactly what you would see in animal studies," he added.
Many animal studies involving rats, ducks, chickens, guppies and earthworms have shown a correlation with lower calorie intake and an extension in life span.
The study further suggests that the lower intake might have an impact on promoting longevity despite controlling factors that included differences in carbohydrates, fat or protein intake, physical activity, obesity and other factors.
"The results of Dr. Willcox's fascinating study comes at a time when there is much confusion among the general public regarding the optimum diet and its association with healthy aging," said Dr. David Curb, president and chief executive officer of the Pacific Health Research Institute, in a written statement.
Diets such as the popular Atkins diet that consist of high protein and fat and low carbohydrates appear to be effective for short-term weight loss for no more than six months to a year; however, there is no evidence of long-term effects, said Dr. Katsuhiko Yano, co-founder of the Research Institute.
"The low caloric intake appears to be the best way not only to lose weight, but for overall health and prolonging the life span for human beings," said Yano.
Willcox said the book on the Okinawan diet he co-wrote with his twin brother, Dr. D. Craig Willcox of Okinawa Prefectural University, and Dr. Makoto Suzuki of Okinawa International University inspired him to do the study.
The book, called "The Okinawan Diet Plan: Get Leaner, Live Longer and Never Feel Hungry," was released in May and reveals a diet plan of foods that are low-fat, water-rich and high in fiber, such as sweet potatoes, soybeans and fish.
Willcox and some members of his research team were also quoted extensively in an article on longevity featured in the current issue of Time magazine called "Living to 100: And Not Regretting It."
Willcox said he and other researchers are hoping to get federal funding to look into online diet support programs. He noted that he also plans to do more studies on dietary factors linked to genetics and longevity.
"One thing we'd like to do is a comparative study of Okinawans in Hawaii and Okinawans in Okinawa because they have different environment exposure but the same genes," Willcox said.